I'm going to plagiarize a question previously asked by graham sanderson <http://www.mail-archive.com/search?l=user@cassandra.apache.org&q=from:%22graham+sanderson%22>, I hope he doesn't mind. The question hasn't been answered but it was at the end of a thread that wasn't directly related to this question, so maybe it hasn't been seen by the right people.
Does anyone know off the top of their head what happens if data is being written at LOCAL_QUORUM to a multi data center setup faster than the inter data center link can handle... something has to block, throw an exception, die, or have unbounded growth (memory, threads, on disk hints etc) somewhere along the line ;-) Thanks in advanced, Elliot